1. Field of the Invention
This invention relates to a lockable slider manipulated to open and close a slide fastener.
2. Prior Art
There have been proposed numerous slide fastener sliders having means locking the slider against unintentional displacement. One such prior locking slider is disclosed in U.S. Pat. No. 3,522,638 in which a locking pawl having a tooth is brought into and out of engagement with some of the coupling elements of the fastener in a slider channel by moving a handle flap (pull tab) pivotally in one or the other direction with its cam portion borne against the upper surface of the flap. A compression spring is adapted to normally hold the flap in horizontal flat position. A difficulty of this prior device is that if for some reason the tooth of the locking pawl fails to engage in the space between adjacent coupling elements as required but instead rides over the upper surfaces of the coupling elements, the locking pawl tends to somewhat press the spring so that the resilient force of the spring is not transmitted to the handle flap, leaving the latter free to wobble itself or hook on the garment or some other objects, resulting in damage to the handle flap or the hooked objects.